This invention relates to a nut to be welded on a steel plate or other weldment component.
In a conventional welding nut as shown in FIG. 13, the angular segment of a square or hexagonal nut is pressed towards its bearing surface side to form axially extending protrusions a. As shown in FIG. 14, to weld this nut to the other weldment component, the protrusions a are abutted against the steel plate b or other weldment component, wherein upon application of a voltage, the protrusions a are melted and the nut is welded to the other component.
The conventional technology has the following problems. With an angular nut as described, the protrusions a are formed by pressing the material of the angular segments over a distance virtually equal to the height of the nut. Accordingly, the material often shifts as it is being pressed. Additionally, given the strong pressing force that is required, as shown in FIG. 13, each outer edge c of the bearing surface will be distorted as the respective ends are pulled. Then, as shown in FIG. 14, upon welding the nut to the steel plate b, a gap d is formed between the outer edge c of the bearing surface and the steel plate b, reducing the strength of the weld.
Usually, in welding a nut, the flat bearing surface of the nut is cladded to the flat top surface of the steel plate, wherein the screwing axis of the nut will be plumb to the surface of the steel plate. However, in the nut as described above, since the outer edge c could be distorted, the two flat surfaces will not be cladded, and the screwing axis may not be welded precisely at right angles to the steel plate, but at a tilt. In this case, the bolt may not screw in securely, or may even be impossible to screw.
In using such an angular nut for welding, its alignment direction upon mounting must be considered, but it is difficult to stipulate a mounting direction for each part when mass produced. Accordingly, the bearing surface of the steel plate or other weldment component must be large enough to enable any resultant alignment of the nut, and thus, the component must be made larger.